Superbugs curbed, but still more to do

17:30Tuesday 22 May 2012

Rates of MRSA in hospitals have fallen significantly in recent years, but over 6% of hospital patients in England still acquire some form of infection during their stay, according to the Health Protection Agency (HPA). The figures come from a major report compiled by the HPA, which looked at the current state of healthcare-acquired infections (HCAI) in hospital, including pneumonia and norovirus as well as “superbugs” such as MRSA. A range of newspapers covered the survey, each emphasising different aspects of the report.

Based on results from a selection of hospitals across England, the report indicates that there have been large reductions in both MRSA and C. difficile rates since the last survey was conducted in 2006. C. difficile infections fell from 2% of patients becoming infected in 2006 to 0.4% in the 2012 report. MRSA fell even more sharply, from 1.8% of patients affected to less than 0.1%.

However, infections with other organisms, such as E. coli and salmonella, are increasing. Infections were most common in the respiratory tract (involving the lungs, windpipe, nose or sinuses), followed by urinary tract infections and infection of surgical sites. Newborns and the elderly were the most likely to have a HCAI, and infections were highest in intensive care units and on surgical wards.

The HPA says that measures that were put in place to fight MRSA and C. difficile infections appear to have driven down infection rates, but that efforts should now be directed at tackling the emerging infections due to other bacteria, as well as maintaining the improvements seen.

The report presents the results of an extensive examination of hospital-acquired infections across England, conducted by the Health Protection Agency (HPA). It looked at a range of healthcare-acquired infections (HCAI), from “superbugs” such as MRSA to outbreaks of norovirus in English hospitals, both NHS and private.

To compile the report, the HPA conducted a survey of 99 NHS acute trusts and five private-sector care organisations between September and November 2011. In total, data from 52,433 patients was analysed and presented in the report. The survey included data on the type of infection (the organism involved), the location of the infection, patient characteristics and hospital characteristics. The survey also collected data on the use of antimicrobial agents such as antibiotics.

Overall, 6.4% of these patients had some form of HCAI (95% confidence interval 4.7% to 8.7%). Private-sector hospitals had a significantly lower prevalence of HCAI compared to NHS hospitals, at a rate of 2.2% (95% CI 1.3–3.8%). Although the difference in rates could be down to better practices in private institutions, it is also possible that it is due to the small size of the included private-sector hospitals, the demographics of the patients treated there or the nature of the services they provide.

Methicillin-resistant Staphylococcus aureus (MRSA) and Clostridium difficile regularly receive prominent news coverage and can be of major concern for patients going into hospital. Infections with these organisms can be deadly, and in recent years national policies for the control and reduction of MRSA and C. difficile transmission in hospitals have been introduced.

The HPA report indicates that less than 0.1% of patients had MRSA infections, and 0.4% had C. difficile infections. The HPA report says that this represents a significant reduction in infections with these organisms since the last survey, published in 2006. Overall MRSA infections have tumbled since the last survey, falling from 1.8% of patients being affected to less than 0.1% over the six-year period. There has also been a five-fold reduction in C. difficile infections during the same time, down from 2% to 0.4%.

The report suggests that recent efforts to tackle MRSA transmission in hospitals have been effective at driving down the prevalence of these infections. Many of these are simple yet effective in nature, such as emphasising regular, thorough hand-washing and swabbing patients to test for MRSA as they are being admitted to hospital.

Despite these improvements, the HPA still emphasises that there needs to be continued focus on these preventative efforts in order to keep the number of these infections low.

While MRSA and C. difficile infections appear to have fallen over the last five years, new types of infections have emerged. A class of organisms called enterobacteriaceae (also known as coliforms) were the most frequently reported HCAI, with 0.9% of the survey populations infected. Enterobacteriaceae include bacteria that are normally found in the human intestine, such as E. coli and salmonella, although there are also newly identified strains.

Approximately 15% of the enterobacteriaceae infections reported during the survey appear to be resistant to some newer antibiotics. The report recommends the creation of new guidance on the control and prevention of these infections in healthcare settings.

The report does not show rates of infections specifically due to norovirus, but the overall rate of general gastrointestinal system infections has also reduced, from 22% of patients to 8.8% from 2006 to 2011.

The prevalence of HCAI infections varied across patient groups and hospital wards. The survey found that prevalence was highest among patients in intensive care units (ICUs) (23.4% of patients) and on surgical wards (8% of patients). This is partly due to the types of procedures conducted in these settings, which are generally associated with an increased risk of infection. In addition to these procedures, ICUs tend to care for the most vulnerable patients: of patients in the ICU, 40.5% were intubated (breathing with the assistance of a ventilator, which involves running a tube down the throat) and this procedure is associated with a risk of pneumonia. Other procedures common in ICUs and surgical wards, such as catheterisation (inserting a tube to drain urine), also are associated with an increased risk of infection.

Healthcare-acquired infections were most common in patients under the age of two (prevalence among patients between one and 23 months old was 8.2%) and in the elderly (prevalence among patients between 65 and 79 years old was 7.4%; over 80 years old it was 6.5%).

Although the exact reasons are not clear, young children and elderly people:

The report says that anywhere from 20% to 40% of HCAIs currently occurring may be preventable. The Department of Health advocates the adoption of “high-impact interventions”, which are evidence-based approaches that can reduce the risk of HCAI. There are interventions that focus on catheter care, ventilator-associated pneumonia, surgical site infections, cleaning and decontamination and chronic wound care. These interventions provide advice on specific steps that can be taken throughout a procedure that reduce the risk of HCAI.

The HPA reports that good hygiene, appropriate use of antibiotics and improved clinical techniques can reduce the risk of HCAIs. Some simple measures to prevent infection or transmission include: